The present invention provides a method for cleaning a pipeline containing particulate matter or other solids debris utilizing a novel crosslinked aqueous gel comprising select copolymers of cellulose ether derivatives.
Numerous methods exist to effect cleaning of the interior of a pipeline of scale and other debris. Mechanical pigs and gelled chemical pigs have been used to remove the scale and other debris. The mechanical pigs are normally solid somewhat bullet shaped devices with rubber baffles, wire brushes or abrasive surfaces to physically scrape the scale and debris from the pipe. The gelled chemical pigs, on the other hand, generally remove the debris by entrainment as the gelled fluid passes through the pipeline.
Various processes utilizing chemical pigs for pipeline cleaning are disclosed in, for example, U.S. Pat. Nos. 3,523,826; 4,216,026; 4,252,465; 4,389,461; 4,416,703 and 4,543,131 and the numerous patents identified therein. The various processes utilize chemical pigs formed from various gelled fluids or emulsions to pick up and carry debris in the pipeline from a point of injection to a point of ultimate recovery. The recovered chemical pigs containing the debris then are broken to separate the debris and permit disposal of the chemical pig. The chemical pigs generally are incapable of reuse after removal from the pipeline. In many instances, due to the limited ability of the chemical pigs to continuously support large quantities of debris as it is collected within a pipeline, large quantities of the chemical pigs must be utilized to ensure that the debris is picked up and maintained at a concentration that can be satisfactorily removed by the chemical pig. Alternatively, a quantity of a debris laden chemical pig is passed through a pipeline to a predetermined location whereupon it is removed and replaced with a new chemical pig to remove additional debris.
It would be highly desirable to provide a gelled fluid pig that could be utilized to remove solid debris from a pipeline, the debris be removed from the fluid and the fluid be utilized to remove additional debris.
Such a fluid would possibly permit smaller fluid volumes to be utilized, multiple uses of the fluid and decreased disposal costs since less overall fluid ultimately must be disposed of upon completion of the cleaning process.